Leaves, stems and seeds powder of neem (Azadirachta indica A. Juss.) used as repellent of Sitophilus zeamais (Coleoptera: Curculionidae) in stored corn

Resumo

Sitophilus zeamais is considered one of the most important pests of stored grain. In order to search alternative methods for controlling this pest the action of neem was evaluated in laboratory (Azadirachta indica A. juss.) in the behavioral and food processes of adults of S. zeamais. In this study extracts produced from three parts of the neem tree (leaves, seeds and peels) were tested. In the verification of the extracts in relation to the repellent, three arenas formed by five plastic boxes connected by polyethylene hose were used. In the test were used 40g of corn treated with 6g of the extracts from leaves, seeds and peels of neem. The verification of the effect of the extracts studied was based on the number of present insects on the test plant (treated containers), and on the number of insects present on the control plant (untreated container). In the repellency analysis, leaves and seeds showed satisfactory results, with repellency indexes (RI) equals to 0.5 and 0.3, respectively, being characterized as repellent plant. The repellency index of the peel extract was 1.1, qualifying the plant as attractive one, to present RI > 1. Therefore, the leaves and seed extracts from neem can be considered as a viable alternative for controlling the Sitophilus zeamais in stored corn.

DOI: http://dx.doi.org/10.14685/rebrapa.v1i1.4